With over 116,000 people homeless in New York City and tens of thousands more on the waitlist for supportive housing, Mayor Bill de Blasio announced today a $2.6 billion plan to create 15,000 units of supportive housing in New York City over the next 15 years.

Half of the 15,000 new supportive housing units will be newly constructed over the next 15 years, while others will be pre-existing scattered-site housing. There are roughly 160,000 New Yorkers on the waitlist for supportive housing.

Started in 1980, the city's supportive housing network of 32,000 units provides residences and resources to those suffering from mental and physical illnesses, trauma, and addiction; in the expanded plan announced today, it will also be available to veterans and survivors of domestic abuse.

"We know there are men, women, and families in our shelters and on our streets that have struggled with mental illness and substance abuse, and we know they have needed a place to live that came with the supports that can make their lives whole again," Mayor de Blasio said at a press conference on Wednesday. “The city of New York is acting decisively. We are not waiting on Albany."

The mayor's decision follows months of back and forth with Governor Cuomo over exactly how much supportive housing to add in the city.

Speaking at the press conference, de Blasio cited a lack of action following his "very public request of the state back in February" for significantly increasing the number of supportive housing units; meanwhile, in September, Cuomo suggested creating 3,900 new units—significantly fewer than de Blasio was calling for—and said that "the city should spend more" on housing.

“The city just did more," de Blasio said Wednesday when pressed on the Governor's remarks. "We are taking responsibility for everything that can be asked of us. We want the state now to get into this and provide support…it’s time for the state to step up.”

"Some" units will be available in 2016, the mayor said, though the final rollout will not be complete until 2030. The city will cover approximately $1 billion of capital costs, while the other $1.6 billion will come from a combination of private developers and low-income tax credits. The annual cost per unit will be approximately $30,000, according to de Blasio's budget director, Dean Fuleihan.

"That is much better obviously than we wind up doing in a shelter or in a jail," Fuleihan said.

Indeed, as of October 2015, the annual cost-per-inmate in the city was $112,665; the average cost to shelter a homeless family, meanwhile, was $37,047 in 2014. A 2014 report from the Department of Health and Mental Hygiene showed that those given supportive housing saved the city $10,100 per tenant per year.

“We want fewer people in Rikers Island because of a mental health or substance abuse problem,” de Blasio said.